Ophthalmologic apparatus

Abstract

An ophthalmologic apparatus includes an optical system for illuminating a subject's eye, an optical system for observing the eye illuminated by the illumination optical system, an alignment detecting system for detecting the alignment of the observation optical system with the eye, and a switchover circuit for switching over a reference allowable range to another range. The observation optical system can observe the eye at at least two different magnifications. The alignment detecting system includes a sensor for receiving reflection light reflected by the eye, a circuit for setting a reference allowable range, an arithmetic circuit for processing a signal output by the sensor and detecting an alignment condition, and a judgment circuit for judging whether the alignment condition detected by the arithmetic circuit is within the reference allowable range set by the range setting circuit.

What is claimed is: 
     
       1. An ophthalmologic apparatus comprising: an optical system for illuminating a subject's eye;   an optical system for observing said eye illuminated by said illumination optical system, said observation optical system being capable of observing said eye at least two different magnifications;   means for detecting the alignment of said observation optical system with said eye, said alignment detecting means judging a condition of the alignment from a predetermined reference allowable range; and   means for switching over said reference allowable range to another range.   
     
     
       2. An ophthalmologic apparatus according to claim 1, wherein said switchover means switches over a reference allowable range according to a magnification of said observation optical system. 
     
     
       3. An ophthalmologic apparatus comprising: an optical system for illuminating a subject's eye;   an optical system for observing said eye illuminated by said illumination optical system, said observation optical system being capable of observing said eye at at least two different magnifications;   means for detecting the alignment of said observation optical system with said eye, said alignment detecting means judging a condition of the alignment from a predetermined reference allowable range; and   means for switching over said reference allowable range to another range;   said element detecting means comprising:   means for receiving reflection light reflected by said eye;   means for setting said reference allowable range;   arithmetic means for processing a signal output by said reflection light receiving means and detecting an alignment condition; and   means for judging whether said alignment condition detected by said arithmetic means is within said reference allowable range set by said range setting means.   
     
     
       4. An ophthalmologic apparatus according to claim 3, wherein said switchover means switches over a reference allowable range according to a magnification of said observation optical system. 
     
     
       5. An ophthalmologic apparatus according to claim 3, wherein said reference allowable range is switched over to a small reference allowable range when said observation optical system is at a high magnification whereas said reference allowable range is switched over to a large reference allowable range when said observation optical system is at a low magnification. 
     
     
       6. An ophthalmologic apparatus comprising: an optical system for illuminating a subject's eye;   an optical system for observing said eye illuminated by said illumination optical system, said observation optical system being capable of observing said eye at least two different magnifications;   means for detecting the alignment of said observation optical system with said eye, said alignment detecting means judging a condition of the alignment from a predetermined reference allowable range; and   means for switching over said reference allowable range to another range;   said alignment detecting means comprising:   means for receiving light reflected by said eye;   means for setting said reference allowable range;   arithmetic means for processing a signal output by said reflection light receiving means and detecting an alignment condition in X-axis and Y-axis directions of the apparatus; and   means for judging whether said alignment condition detected by said arithmetic means is within said reference allowable range set by said range setting means.   
     
     
       7. An ophthalmologic apparatus according to claim 6, wherein said switchover means switches over a reference allowable range according to a magnification of said observation optical system. 
     
     
       8. An opthalmologic apparatus according to claim 6, wherein said reference allowable range is switched over to a small reference allowable range when said observation optical system is at a high magnification whereas said reference allowable range is switched over to a large reference allowable range when said observation optical system is at a low magnification. 
     
     
       9. An ophthalmologic apparatus comprising: an optical system for illuminating a subject's eye;   an optical system for observing said eye illuminated by said illumination optical system, said observation optical system being capable of observing said eye at at least two different magnifications;   means for detecting the alignment of said observation optical system with said eye, said alignment detecting means judging a condition of the alignment from a predetermined reference allowable range; and   means for switching over said reference allowable range to another range;   said alignment detecting means comprising;   means for receiving light-reflected by said eye;   means for setting said reference allowable range;   arithmetic means for processing a signal output by said reflection light receiving means and detecting an alignment condition in a Z-axis direction of said apparatus; and   means for judging whether said alignment condition detected by said arithmetic means is within said reference allowable range set by said range setting means.   
     
     
       10. An ophthalmologic apparatus according to claim 9, wherein said switchover means switches over a reference allowable range according to a magnification of said observation optical system. 
     
     
       11. An ophthalmologic apparatus according to claim 9, wherein said reference allowable range is switched over to a small reference allowable range when said observation optical system is at a high magnification whereas said reference allowable range is switched over to a large reference allowable range when said observation optical system is at a low magnification.